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Salt metathesis reactions between pyridyl-methylene-cyclopentadienyl lithium salt and LnCl3 followed by the addition of two equivalents of LiCH2SiMe3 afforded a series of constrained-geometry-configuration rare-earth metal bis(alkyl) complexes (Cp′CH2-Py)Ln(CH2SiMe3)2(THF)n (Py = C5H4N, Cp′ = C5H4 (Cp), Ln = Sc,n = 0 (1); Cp′ = C9H6 (Ind), Ln = Sc,n = 0 (2); Cp′ = 3-Me3Si-C9H5 (3-Me3Si-Ind), Ln = Sc,n = 0 (3a), Ln = Lu (3b), Y (3c),n = 1; Cp′ = 2,7-(tBu)2C13H8 (2,7-(tBu)2-Flu), Ln = Sc (4a),n = 0, Ln = Lu (4b), Y (4c),n = 1) in moderate to good yields, which were characterized by NMR spectroscopy and single-crystal X-ray diffraction (for complex3a). In the presence of [Ph3C][B(C6F5)4] and AliBu3, these complexes displayed different performances towards styrene polymerization. Rare-earth metal bis(alkyl) precursors bearing Cp, Ind, and 3-Me3Si-Ind segments exhibited very low catalytic activity to afford syndiotactic polystyrene. All electron-donatingtBu substituted complexes4a,4b, and4c showed very high activity and perfect syndiotactivity (rrrr > 99％), producing high molecular weight polystyrene (up to 54.1 × 104) with relatively narrow molecular distribution (PDI = 1.28?2.49).